1. Field of the Invention
Embodiments of the invention relate to a color filter plate and an organic light emitting display (OLED) device, and more particularly, to a color filter plate and an OLED device being capable of preventing a visibility degradation by an ambient light and improving transmissivity and a method of fabricating the OLED device.
2. Discussion of the Related Art
Recently, flat panel display devices, such as a plasma display panel (PDP), a liquid crystal display (LCD) device, and an OLED device, are widely researched and used.
Among these flat panel display devices, since the OLED device as a self-emission type display device does not implement a backlight unit, the OLED device may have advantages of light weight and thin profile.
In addition, the OLED device has excellent characteristics of a viewing angle, a contrast ratio, power consumption, a response time, production costs, production yield, and so on.
An organic emitting diode of the OLED device may include first and second electrodes and an organic emitting layer, which includes a hole transporting layer (HTL), an electron transporting layer (ETL) and an emitting material layer (EML) therebetween, between the first and second electrodes.
In addition, to improve an emitting efficiency, the organic emitting layer may further include a hole injection layer (HIL) between the first electrode and the HTL and an electron injection layer (EIL) between the second electrode and the ETL.
When voltages are applied to the first and second electrodes, the holes from the first electrode and the electrons from the second electrodes are combined in the EML such that excitons are generated. The excitons are transited from an exciting state to a ground state such that the light is emitted from the organic emitting layer.
FIG. 1 is a schematic view illustrating a related art OLED device.
Referring to FIG. 1, the OLED device 10 includes the second electrode (not shown) as a cathode. To facilitate the electron injection and increase the emitting efficiency, the second electrode may be formed of a metallic material, e.g., magnesium, magnesium-silver alloy, aluminum, lithium-aluminum alloy and calcium. However, the second electrode of the above metallic material has a high light reflectance. As a result, the ambient light is reflected by the second electrode such that the visibility of the OLED device 10 is degraded. Namely, the ambient contrast ratio of the OLED device 10 is decreased.
To prevent the above problem, a circular polarization plate, which includes a linear polarization plate 70 and a ¼ retardation plate 30, is disposed on or over the second electrode.
However, when the circular polarization plate is used, the light from the organic emitting layer of the OLED device 10 (i.e., the internal light) is absorbed by the circular polarization plate such the OLED device 10 may have that the transmissivity below about 43%. Namely, the transmissivity of the OLED device 10 is remarkably decreased. To compensate the decreased transmissivity, the power consumption of the OLED device 10 should be increased.
On the other hand, since the circular polarization plate is susceptible to damage from moisture, a tri-acetyl-cellulose (TAC) film is attached to lower and upper sides of the circular polarization plate to protect the circular polarization plate from the moisture.
However, since the TAC film has a hard (i.e., solid or stiff) property, the circular polarization plate including the TAC films is difficult to use for a flexible OLED device.